Why do these companies like the JVM so much? Twitter, and now Facebook. Does it have that great of performance?
As far as mainstream languages go, only C and C++ have a performance and scalability edge, but C++ at least comes with more complexity. JVM seems to hit the performance:complexity sweet spot.
As much as I love to rag on java the language the JVM is generally a solid piece of work that makes reasonable tradeoffs.
The biggest problem I've had with the CLR is threads bouncing between CPUs but I'd attribute that to Windows as I worked around it with some Win32 calls to pin threads to processors.
Can't really compare to LLVM, I haven't personally encountered any of the known llvm bugs (clang to be fair) with Obj-C.
I'd try to increase the revenue my server generates rather than decrease the cost of servers, but I'm the kind of guy who thinks it's possible to pull more than 5 cents an hour in revenue from a server, but if you only get 5 cents per hour then it would be important to use linux so you maintain your 2 cent per hour profit margin.
Note that Java compares very favorably with C. (Of course, the real thing to take away from that chart is: why don't all the JVM users switch to Haskell? It's more concise, safer, and has a better community.)
If you read the methodology listed in their FAQ, they state in bold - "Time measurements include program startup time".
http://shootout.alioth.debian.org/help.php#time
If you read the section "What about Java?" they mention ADDITIONAL measurements, which are only shown on the Help page, and indicate how little difference JVM startup time makes once these programs have run for 5 seconds and 20 seconds.